ALPP and rhabdomyosarcoma: For example, positive PLAP immunostaining has been described to occur in 0–100% of adenocarcinomas of the ampulla of Vater [4, 35], 0–38% of gastric adenocarcinoma [4, 35], 0–100% of rhabdomyosarcomas [44, 56], 20–80% of high‐grade serous carcinomas of the ovary [43, 59], and 0–18% of clear cell renal cell carcinomas [4, 35].